The yarn architecture of 3-D braided composites products by the four-step 1×1 braiding technique has been studied by means of a control volume method in conjunction with experimental investigation and a numerical...The yarn architecture of 3-D braided composites products by the four-step 1×1 braiding technique has been studied by means of a control volume method in conjunction with experimental investigation and a numerical method, respectively. An ellipse assumption for the cross-section of yarn was proposed in this analysis method with considering the yarn size and yarn-packing factor. Two types of local unit cell structures were identified for 4-step braided composites by considering the nature of the braiding processes and by observing the sample cross-sections. The relationship between the braiding procedure and the properties for 3-D braided structural shapes was established. This method provides the basis for analyzing stiffness and strength of 3-D braided composites.展开更多
In this paper three types of dual- chamber shock- struts are considered in dynamic analyses of landing-gear behavior during impact and taxi. Their dynamic characteristics are compared with each other according to calc...In this paper three types of dual- chamber shock- struts are considered in dynamic analyses of landing-gear behavior during impact and taxi. Their dynamic characteristics are compared with each other according to calculation results, and some conclusions are presented.It is very helpful for selecting a suitable type of dual-chamber shock-strut in landing-gear design.展开更多
An efficient method for helicopter rotor fault diagnosis was proposed using diagnostic matrix and its software framework was developed.The diagnostic matrix was extracted by the way of simulating the quantitative mode...An efficient method for helicopter rotor fault diagnosis was proposed using diagnostic matrix and its software framework was developed.The diagnostic matrix was extracted by the way of simulating the quantitative models of damaged and undamaged rotor systems.The conflicts were recognized by the virtual symptom sensor based on the dependencies between symptoms and faults.Diagnostic candidates were generated by the Boolean hitting algorithm.The proposed method provides multi-fault real-time diagnostic capability and it is suitable for the synthetic health monitoring of complex systems.展开更多
Current developments on fatigue life prediction methods have been systematically reviewed.In con- sideration of the irreversibility of energy dissipation during fatigue damage process,the main contents for fatigue dam...Current developments on fatigue life prediction methods have been systematically reviewed.In con- sideration of the irreversibility of energy dissipation during fatigue damage process,the main contents for fatigue damage estimation and localized equivalence as well as simulation models have been established.A frame of energy-based fatigue life prediction method has been proposed,meanwhile, the procedure in application to a practical structure component has been described.展开更多
基金Aeronautical Science Foundation of China ( 99B2 3 0 0 1)
文摘The yarn architecture of 3-D braided composites products by the four-step 1×1 braiding technique has been studied by means of a control volume method in conjunction with experimental investigation and a numerical method, respectively. An ellipse assumption for the cross-section of yarn was proposed in this analysis method with considering the yarn size and yarn-packing factor. Two types of local unit cell structures were identified for 4-step braided composites by considering the nature of the braiding processes and by observing the sample cross-sections. The relationship between the braiding procedure and the properties for 3-D braided structural shapes was established. This method provides the basis for analyzing stiffness and strength of 3-D braided composites.
文摘In this paper three types of dual- chamber shock- struts are considered in dynamic analyses of landing-gear behavior during impact and taxi. Their dynamic characteristics are compared with each other according to calculation results, and some conclusions are presented.It is very helpful for selecting a suitable type of dual-chamber shock-strut in landing-gear design.
文摘An efficient method for helicopter rotor fault diagnosis was proposed using diagnostic matrix and its software framework was developed.The diagnostic matrix was extracted by the way of simulating the quantitative models of damaged and undamaged rotor systems.The conflicts were recognized by the virtual symptom sensor based on the dependencies between symptoms and faults.Diagnostic candidates were generated by the Boolean hitting algorithm.The proposed method provides multi-fault real-time diagnostic capability and it is suitable for the synthetic health monitoring of complex systems.
文摘Current developments on fatigue life prediction methods have been systematically reviewed.In con- sideration of the irreversibility of energy dissipation during fatigue damage process,the main contents for fatigue damage estimation and localized equivalence as well as simulation models have been established.A frame of energy-based fatigue life prediction method has been proposed,meanwhile, the procedure in application to a practical structure component has been described.
